529.3: Duncan, David Ewing. Calendar: Humanity’s Epic Struggle to Determine a True and Accurate Year. New York: Avon, 1998. 241 pp. ISBN 0-380-97528-9.
529 is a curious section in the DDC. 520s are astronomy, but the last section in the division–529–is classed as chronology. This is because for many millennia, cultures have counted their days and nights by the sun and the stars. Long before electric wristwatches and atomic clocks, the hours of the day were tolled out by bell towers and sun sightings.
While Gould’s book (here) was superficial and condescending, David E. Duncan’s Calendar is vast and learned. You can tell just from the first chapter that the author consulted as many sources as is possible for this book. His goal is to track the evolution of the modern 12-month, 365-day (or 366) from its earliest form to the present. Along the way, he weaves a thread through Cro-Magnon bone carvers, Egyptian pharoahs, Indian mathematicians, and Catholic philosophers.